Four-stroke explosion engine



April 22, 1941. M. A. VIOLET FOUR-STROKE EXPLOSION ENGINE Filed Oct. 21,1938 Patented Apr. 22, 1941 FOUR-STROKE EXPLOSION ENGINE Marcel AchilleViolet, Nanterre, France Application October 21 In France 4 Claims.

At the present time a great number of distribution devices for internalcombustion engines of the four stroke type are already known, thesedevices including valves, sliding or oscillating sleeves or the like,rotating valves, and so on. Rotary valves, in particular, have theadvantage 1938, Serial No. 236,308

ctober 23, 1937 of being noiseless, when working at very high speed, ofmaking it possible to give the explosion chamber a suitable shape, andso on. However, such valves suffer from the disadvantage that, by reasonof the fact that they are heated up to a very high temperature by theexhaust gases, proper lubrication is rendered extremely diflicult andmakes it necessary to provide play which prevents a satisfactory fluidtightness being obtained.

The chief object of the present invention is to provide a device,including a rotary valve, which avoids these drawbacks.

According to a feature of the present invention, most of the exhaust gasis evacuated through orifices opened by the piston at the end of thedownward stroke thereof. With such an arrangement, it is possible toopen the distribution valve for the outflow of the exhaust gases onlywhen the cylinder contains but a small part of the residual gases, theseremaining gases being expanded and cooled. Consequently it is possibleto avoid the heating of the rotary valve to an excessive temperature.

According to another feature of the present invention, I improve thefilling of the cylinder with fresh gases by producing, at the end of theinlet stroke, through the orifices above mentioned, a supplementarysuction. This permits of obtaining a further infiow of fresh gases intothe engine, although the cylinder and the explosion chamber are alreadyfilled with fuel mixture at this time. However, it is necessary to takecare that the suction is not too great, in order to avoid losing acertain amount of fresh gases which would escape through said orifices.

Other objects and advantageous features of the present invention willbecome apparent from the following detailed description of two specificembodiments thereof.

Two embodiments of the present invention will be hereinafter described,with reference to the accompanying drawing, given merely by way ofexample, and in which:

Fig. 1 is a vertical section of the cylinder of a single cylinder engineprovided with a distribution system made according to the presentinvention, the piston being shown, in this view, at the end of itsdownward stroke;

Fig. 2 is a diagrammatic horizontal section of a multi-cylinder engineprovided with dis tribution means made according to the presentinvention.

In Fig. 1, reference numeral I designates the cylinder; 2 is the piston,and 3 the rotary valve, turning at half-speed, which places the insideof the cylinder in communication successively with the exhaust pipe 4and with the inlet pipe 5. Immediately above the level of the top of thepiston when it is in the position shown by the drawing, there isprovided an orifice 6. When the piston is in the position shown, theorifice 6 connects the inside of the cylinder with an exhaust pipe 1provided with a light check valve 8. A chamber 9, the volume of which issubstantially greater than the volume swept in the cylinder by a fullstroke of the piston is provided between orifice 6 and check valve 8.This chamber is to ensure a smooth running of the engine under allconditions, especially at low speeds and when idling.

The operation of the engine above described is the following:

Piston 2, being in its downward stroke, finally reaches the positionshown by Fig. 1. As soon as orifice 6 is opened, the high pressure gasesescape, for the most part, through orifice 6 and pipe I. As soon aspiston 2 has moved bad: in the upward direction and has covered orifice6, rotary valve 3 opens the connection with pipe 4 and the burnt gasescontinue to escape from the cylinder, passing now into said exhaust pipeBut as most of the hot gases have already escaped through pipe 1, theresidual gases which now flow through the rotary valve are alreadyexpanded and consequently somewhat cooled, so that they do not heat therotary valve excessively. At the end of the upward stroke, the upperface of the piston is at the position indicated by dotted line l0. Assoon as the piston starts moving down, valve 3 comes into a positionsuch that the inside of the cylinder is no longer connected with theoutlet pipe 4 but is now connected with the inlet pipe 5. Suction offresh gases into the cylinder now takes place. On the other hand,immediately after the escape of the exhaust gases through pipe I, checkvalve 8 will have come back onto its seat, and the gases remaining inchamber 9 will by this time have cooled down and will have produced apartial vacuum in said chamber. Therefore, now, atthe end of the suctionstroke, when orifice 6 is uncovered by piston 2, the vacuum chamber 9will suck partof the gases out of the cyl- Although I have described adevice according to the invention as applied to a single cylinderengine, it can be applied to a multi-cylinder engine. Fig. 2 shOWS, byway of example, an embodiment of a four stroke engine provided with suchan exhaust arrangement. In this case, the four cylinders A, B, C, and Dare each provided with an exhaust pipe 20A, 20B, 20C,'and 20D,respectively, corresponding to pipe I of the preceding embodiment. Theseexhaust pipes are bent in the direction of the gaseous stream and theyopen into a manifold 2! closed at 22 and open at 23. Due to the bent-endportions and the direction of flow of the gases in the manifold 2| theindividual pipes are subjected to an induction effect which tends toproduce a slight vacuum therein. The manifold M is provided, at asuitable point, with a check valve corresponding to check valve 8 of thefirst embodiment, consisting, in the example illustrated by the drawing,of a valve 30. With this arrangement, the necessity of providing theexhaust pipe of each cylinder with a similar check valve is avoided.

In other respects, the distributing means of the respective cylindersare similar to those shown by Fig. 1. In the interest of simplicitythese are not shown in Fig. 2. It will be readily understood that, whenone of the four cylinders is in a position near the end of its chargingstroke and its exhaust port 6 has been uncovered, the suction producedin the manifold 2| and the individual exhaust pipe of the cylinder beingcharged by the cylinder which is in the exhaust stroke facilitates thischarging in a substantially similar manner as above explained inconnection with the embodiment of the invention shown in Fig. 1 of thedrawing.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practical and efilcient embodiments of the presentinvention, it should be well understood that I do not wish to be limitedthereto as there might be changes made in the arrangement, dispositionand form of the parts without departing from the principle of thepresent invention as comprehended within the scope of the appendedclaims.

What I claim is:

1. Method of operating a four cycle internal combustion engine providedwith a rotary distributor valve having inlet and exhaust means forpreventing subjection of the valve to excessive temperature of exhaustgas and for increasing the amount of fresh charge charged into thecylinder of the engine during the charging stroke, said methodcomprising passing a part of the hot exhaust gases of a cylinder towardthe end of the working stroke into an auxiliary chamber from a portlocated near the bottom position of the upper surface of the piston,said port, being uncovered-before the exhaust means of the distributorvalve, closing said port during the exhaust stroke, creating a partialvacuum in said auxiliary chamber and putting said chamber incommunication with the interior of the cylinder for an extremely shorttime through said port at the end of the suction stroke of the piston towithdraw additional burned gas and facilitate charging the cylinder withfresh gas through the inlet means of the distributor valve.

2. Method of operating a four cycle internal combustion engine providedwith a rotary dlstributor valve having inlet and exhaust means forpreventing subjection of the valve to excessive temperature of exhaustgas and for increasing the amount of fresh charge charged into thecylinder of the engine during the charging stroke, said methodcomprising passing a part of the hot exhaust gases of a cylinder towardthe end of the working stroke into an auxiliary chamber from a portlocated near the bottom position of the upper surface of the piston,said port being uncovered before the exhaust means of thedlstributorvalve, closing said port during the exhaust stroke, creating a partialvacuum in said auxiliary chamber by cooling the gases therein during theexhaust stroke and the major portions of the charging stroke of thepiston, opening communication between said auxiliary chamber and theinterior of the cylinder for a short period toward the end of thecharging stroke, to suck out additional stratifled burned gas and todraw additional fresh charge into the cylinder through the inlet meansof the distributor.

3. The method of operating a multi-cylinder, foun stroke cycle internalcombustion engine, each cylinder of which has a rotary distributor valveprovided with inlet and exhaust means, and each cylinder having asupplementary exhaust port in its wall above but near the lowestposition of the upper surface of its piston, said supplementary exhaustports opening into auxiliary chambers, and a common exhaust pipe intowhich said chambers open in the direction of flow of the exhaust gasesin said pipe for preventing excessive heating of the distributor valveby hot exhaust gases and increasing the amount of fresh charge chargedinto the cylinders, said method comprising passing part of the exhaustgases out of the cylinders through said supplementary exhaust ports tosaid auxiliary chambers when the pistons are near their lower positionsin the working strokes before opening the exhaust means of thedistributor valves, opening the exhaust means of the distributor valvesduring the exhaust strokes of the pistons, producing partial vacuum insaid auxiliary chambers during the exhaust and major portion of thecharging strokes of the respective portions by the induction effect ofthe exhaust gases of the other cylinders flowing in the exhaust pipe,opening the cylinders to their corresponding auxiliary chambers forextremely short periods near the end of the charging strokes so that thevacuum in said auxiliary chambers will suck out stratified burnt gasesfrom the cylinders and draw additional fresh charge thereinto.

4. In a four stroke cycle internal combustion engine comprising a.cylinder having a reciprocatory piston therein, a rotary distributingvalve having intake and exhaust means therein, located at the upperendof the cylinder, and said cylinder having an auxiliary exhaust portlocated in its side wall at a point immediately above the upper face ofthe piston when in its lowest position, an exhaust chamber for receivingthe exhaust gases passing out of said auxiliary exhaust port; means foroperating the distributing valve to open the exhaust means thereof afterthe exhaust gases have passed out of the auxiliary exhaust port to suchextent as amazes to reduce the pressure in the cylinder to substantiallyatmospheric pressure, whereby the exhaust means of the distributor valvereceives only expanded and cooled exhaust gases, means for creating apartial vacuum in said exhaust chamber during the exhaust stroke andmajor portion of the charging stroke, whereby additional stratifiedburned gases are sucked out oi the cylinder toward the end of thecharging stroke by the vacuum in the exhaust chamber and additionalfresh charge is sucked into the 5 cylinder to replace said additionalburned gases.

MARCEL ACHILLE VIOLET.

